The transformation is astonishing. What used to be a hilly mound between braided rivers has been summarily flattened, and all that remains of the previous industrial landscape is a single tarmac road snaking across a plateau of barren earth. Raised embankments, a few metres high, mark the egg-shaped perimeter of what will one day be the stadium proper. Outside this proto-arena a brand new water feature has appeared, approximately the size of an Olympic-sized swimming pool but rather more irregularly-shaped and full of muddy liquid. I don't think this hole is part of the final plans, but it certainly looks a lot cheaper than Zaha Hadid's genuine Aquatics Centre planned for the opposite side of the river. Whatever, it is now possible to stand on the Greenway bridge and to imagine what might be about to appear. The great knockdown may be complete, but the grand build up will take considerably longer.

There are now none-too-subtle hints that this area is evolving from a demolition zone into a building site. Two huge blocks of multi-storey portakabins await the imminent arrival of thousands of construction workers. A big green footbridge crosses Marshgate Lane so that everyone can pass safely from one side to the other without being knocked down by a passing truck. Spiked yellow buoys block off all river access into the site, lest some cavalier boatman might sail in and compromise hard-earned security. And outside, beyond the blue-walled perimeter, numerous newly-erected road signs prepare to direct heavily-laden lorries to one of 14 different entrance gates. The concrete is coming, and the world's athletes will only be 50 months behind.